spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Suetsugu, S.
Right arrow Articles by Takenawa, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Suetsugu, S.
Right arrow Articles by Takenawa, T.
Journal of Cell Science 114, 4533-4542 (2001)
© 2001 The Company of Biologists Limited

RESEARCH ARTICLE

Enhancement of branching efficiency by the actin filament-binding activity of N-WASP/WAVE2

Shiro Suetsugu1,2, Hiroaki Miki1, Hideki Yamaguchi1,2, Takeshi Obinata3 and Tadaomi Takenawa1,2,*

1 Department of Biochemistry, Institute of Medical Science, University of Tokyo and
2 CREST, JST, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
3 Department of Biology, Faculty of Science, Chiba University Faculty of Science, Chiba University, Yayoicho, Inageku, Chiba, 263-8522, Japan

*Author for correspondence (e-mail: takenawa{at}ims.u-tokyo.ac.jp)

Accepted September 8, 2001

The actin-related protein (Arp) 2/3 complex is an essential regulator of de novo actin filament formation. Arp2/3 nucleates the polymerization of actin and creates branched actin filaments when activated by Arp2/3-complex activating domain (VCA) of Wiskott-Aldrich syndrome proteins (WASP family proteins). We found that the branching of actin filaments on pre-existing ADP filaments mediated by the Arp2/3 complex is twice as efficient when Arp2/3 was activated by wild-type neural WASP (N-WASP) or WASP-family verprolin-homologous protein (WAVE) 2 than when activated by the VCA domain alone. By contrast, there was no difference between wild-type N-WASP or WAVE2 and VCA in the branching efficiency on de novo filaments, which are thought to consist mainly of ADP-phosphate filaments. This increased branching efficiency on ADP filaments is due to the basic region located in the center of N-WASP and WAVE2, which was found to associate with ADP actin filaments. Actin filaments and phosphatidylinositol bisphosphate (PIP2) associate with N-WASP at different sites. This association of N-WASP and WAVE2 with actin filaments enhanced recruitment of Arp2/3 to the pre-existing filaments, presumably leading to efficient nucleation and branch formation on pre-existing filaments. These data together suggest that the actin filament binding activity of N-WASP and WAVE2 in the basic region increases the number of barbed ends created on pre-existing filaments. Efficient branching on ADP filaments may be important for initiation of actin-based motility.

Key words: N-WASP, WAVE, Arp2/3 Complex, Actin, Capping Protein






© The Company of Biologists Ltd 2001